WASHINGTON — Attorney General Eric Holder yesterday turned in his homework: a three-page letter to federal judges affirming that the Obama administration recognizes the courts’ power to strike down law.

He had to put in writing that basic tenet of US government after President Obama warned Monday that “unelected” Supreme Court justices should not dare overturn his historic ObamaCare legislation.

“The long-standing, historical position of the United States regarding judicial review of the constitutionality of federal legislation has not changed,” Holder wrote in the letter.

Smith is part of the three-judge panel of the 5th US Circuit Court of Appeals hearing a challenge to ObamaCare separate from the case currently under deliberation by the Supreme Court.

The president’s admonishment that “unelected” judges should not “take an unprecedented, extraordinary step of overturning a law that was passed by a strong majority of a democratically elected Congress” also ignited a firestorm of criticism that Obama was trying to intimidate the high court.

While bowing to the power of the judiciary, Holder still defended his boss in the letter — which was actually about a half-page short of the three-page, single-spaced letter ordered by Judge Smith.

Holder wrote that “the president’s remarks were fully consistent with the principles” of judicial review of laws passed by Congress.

“While duly recognizing the courts’ authority to engage in judicial review, the Executive Branch has often urged courts to respect the legislative judgments of Congress,” the attorney general noted in the letter.

“The Supreme Court has often acknowledged the appropriateness of reliance on the political branches’ policy choices and judgments,” wrote Holder.

He cited several cases in which the high court deferred to decisions of Congress, because its “members take the same oath [judges] do to uphold the Constitution of the United States.”

Still, the backlash against Obama’s rhetoric toward the Supreme Court showed no sign of abating.

Senate Minority Leader Mitch McConnell (R-Ky.) advised the president to “back off” from the justices.

“Respectfully, I would suggest the president back off,” McConnell said in a speech to the Rotary Club of Lexington, Ky.

”Let the court do its work. Let our system work the way it was intended. The stability of our system and our laws and our very government depends on it. And the duties of the presidency demand it,” he said.

McConnell accused Obama of mounting “a political campaign to delegitimize the Supreme Court.”

The high court last week heard three days of oral arguments in the ObamaCare case, with the court’s conservative majority signaling that the law likely will be struck down as unconstitutional.